Electrochemical Investigation of Meloxicam Drug as a Corrosion Inhibitor for Mild Steel in Hydrochloric and Sulfuric Acid Solutions

Inhibition effects of meloxicam drug on mild steel corrosion in 1 M HCl and 0.5 M H2SO4 solutions have been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency (IE) was found to increase with increasing the inhibitor concentration in HCl solution. However, the IE was increased in H2SO4 solution with increasing the meloxicam concentration up to 200 ppm and then it was decreased. Maximum inhibition efficiency of 92 and 95% has been achieved at 400 and 200 ppm meloxicam in 1M HCl and 0.5M H2SO4, respectively. Adsorption of meloxicam on the surface of mild steel follows Langmuir isotherm. Potentiodynamic polarization measurements indicated that meloxicam is a mixed-type inhibitor. The effect of temperature on the corrosion rate of mild steel was studied in acidic media both in the absence and presence of meloxicam drug. Some thermodynamic parameters were computed from the effect of temperature on the inhibition process.